Role of junctional adhesion molecule-like protein in mediating monocyte transendothelial migration.
OBJECTIVE
Monocyte migration across the vascular endothelium of blood vessels is a key early event in atherosclerosis. The mechanisms underlying monocyte transendothelial migration (TEM), however, are still not completely understood. Here we studied the role of junctional adhesion molecule-like protein (JAML) in regulating monocyte TEM.


RESULTS
Firstly, by Western blot and flow cytometry, we showed that JAML was strongly expressed in monocytes and monocyte surface expression of JAML was upregulated by monocyte chemotaxis protein-1 stimulation. Both monocyte adhesion to and migration across tumor necrosis factor-alpha (TNFalpha) preactivated human microvascular endothelial cell (HMEC-1) monolayers were dose-dependently reduced by anti-JAML antiserum or soluble extracellular JAML recombinant. Secondly, short-term exposure of human monocytes and THP-1 cells to advanced glycation end products increased cell surface JAML expression, which was correlated with enhanced cell adhesion and TEM. In contrast, knockdown of JAML in THP-1 monocytes decreased both adhesion and transmigration of THP-1 monocytes. Finally, direct binding assay of the soluble JAML to HMEC-1 monolayers suggested that endothelial coxsackie and adenovirus receptor (CAR) may serve as one of the ligands for JAML.


CONCLUSIONS
Monocytic JAML plays a critical role in regulating monocyte TEM probably via binding to the endothelial CAR and other tight junction-associated adhesive molecules.
Guo
Ya-Lan
YL
Jiangsu Diabetes Research Center, State Key Laboratory of Pharmaceutical Biotechnology, School of Life Science, Nanjing University, Nanjing, China 210093.
Bai
Rui
R
Chen
Celia X-J
CX
Liu
Dan-Qing
DQ
Liu
Yuan
Y
Zhang
Chen-Yu
CY
Zen
Ke
K
D000256:Adenoviridae / Q000502:physiology; D050197:Atherosclerosis / Q000473:pathology / Q000503:physiopathology; D015815:Cell Adhesion Molecules / Q000235:genetics* / Q000378:metabolism; D002463:Cell Membrane Permeability; D002465:Cell Movement / Q000502:physiology*; D018932:Chemokine CCL2 / Q000502:physiology; D017931:DNA Primers; D004730:Endothelium, Vascular / Q000166:cytology / Q000502:physiology* / Q000648:ultrastructure; D004770:Enterovirus / Q000502:physiology; D005434:Flow Cytometry; D005786:Gene Expression Regulation; D006801:Humans; D062726:Junctional Adhesion Molecules; D018613:Microscopy, Confocal; D009000:Monocytes / Q000502:physiology*; D011991:Receptors, Virus / Q000502:physiology; D011994:Recombinant Proteins / Q000378:metabolism; D019108:Tight Junctions / Q000502:physiology; D017539:Tunica Intima / Q000473:pathology / Q000502:physiology
C111835:CCL2 protein, human; D015815:Cell Adhesion Molecules; D018932:Chemokine CCL2; D017931:DNA Primers; D062726:Junctional Adhesion Molecules; D011991:Receptors, Virus; D011994:Recombinant Proteins; C085301:adenovirus receptor